Session D7 - Hadron Physics.
ORAL session, Saturday afternoon, May 01
Governor's Square 16, Adam's Mark Hotel
Absolute differential crossections for pion-nucleon charge exchange (CEX), \pi^-+p\to\pi^0+n, are extracted from experiments E913 and E958 at Brookhaven National Laboratory. The Crystal Ball multi-photon spectrometer was used to measure the energy and trajectory of individual photons from \pi^0 decay. The Crystal Ball covers \sim93% of 4\pi sr for single photons, allowing the measurement of a complete CEX angular distribution except for the most forward angles at the higher momenta. Particular attention has been devoted to beam normalizations and momentum calibrations. Data in the momentum interval of the \Delta resonance (148 to 323 MeV/c) have been submitted for publication. This presentation will concentrate on the analysis of the data at both lower and higher momenta, which extend to the Roper resonance region. Comparison will be made to recent partial-wave analyses.